1. Field of the Invention
The present invention relates to a brake assembly for a motorcycle provided with a hydraulically driven front wheel brake and rear wheel brake, for relational control of the two brakes.
2. Description of Background Art
A motorcycle brake actuation is carried out using a brake lever provided on the handlebar and a brake pedal provided adjacent to a step. Braking force is distributed to the front wheel brake and rear wheel brake according to the actuation of each of the actuating means.
In Japanese Patent Laid-open Publication No. Hei. 7-196068, for example, an example is disclosed using, partial electronic control. The brake system of this example is shown in FIG. 3.
A front wheel brake 02 and a rear wheel brake 05 are hydraulic brakes. A lever master cylinder 07 is provided on a brake lever of an actuating means. A pedal master cylinder 012 is provided on a brake pedal 011.
A lever hydraulic system 08, extending from the lever master cylinder 07, is connected to the front wheel brake 02, a pedal hydraulic system 013 extending from the pedal master cylinder 012 is connected to one port of the three port type rear wheel brake 05, a hydraulic circuit 014 branching from the pedal hydraulic system 013 is connected to a secondary master cylinder 010, and the output of the secondary master cylinder 010 is connected to the other two ports of the rear wheel brake 05 through a control valve 016.
A brake switch 04 opened and closed by rotation of the brake lever 06 is provided on the brake lever 06. A pressure sensor 041 for detecting hydraulic pressure is provide in the lever hydraulic system 08, a control unit 031 determines a hydraulic pressure to be generated at the secondary master cylinder 010 based on each of the detection signals from the brake switch 040 and the pressure sensor 041, and actuates an actuator 033 via a relay 032, so that the secondary master cylinder 010 generates the hydraulic pressure as determined. These devices constitute an electronic braking system.
When the brake pedal 011 is actuated independently, only the rear wheel brake 05 side is actuated dissociated from the front wheel.
When the brake lever 06 is actuated independently, or at the same time as the brake lever 011, the front wheel brake 02 is actuated by hydraulic pressure of the lever master cylinder 07, and the actuator 033 is actuated based on hydraulic pressure of the lever hydraulic system 08 to generate necessary hydraulic pressure in the secondary master cylinder 010 so that the rear wheel brake is actuated by the control valve 016.
A structure for supplying hydraulic pressure for two hydraulic systems, namely hydraulic pressure for the pedal hydraulic system 013 and hydraulic pressure through the control valve 016 of the electronically controlled secondary master cylinder 010, is provided in the rear wheel brake 05, and there is a need for separate piping for the two systems in the rear brake. Also, the pedal hydraulic system 013 branches into two sections, with pipes leading to the rear wheel brake 05 and to the secondary master cylinder 010, and the control valve 016 is located between the secondary master cylinder 010 and the rear wheel brake 05. This all means that the structure has many components and is complicated, and the operation of installing the piping and also maintenance can not be carried out easily.
The layout of the piping is also subject to restrictions, and there is little degree of freedom in the design.
The rear wheel brake receiving the hydraulic pressure from two systems requires pistons for the respective pressure systems in the brake caliper, and in order to prevent partial contacting of a pad (binding) when each of the pressure systems is independently input, pistons are provided at three places and a caliper structure necessary to separate the systems becomes complicated.
Also, since there are two independent pressure systems in the rear wheel brake, when hydraulic pressure is activated at the same time as simultaneous actuation of the first and second brake actuating means, mutual interference occurs between them and the providing of the actuator 033 and control valve 016 in order to improve this situation is difficult and control is complicated.
The present invention has been conceived in view of the above described problems, and the object of the invention is to provide a brake assembly for a motorcycle that carries out simple control without causing interference between hydraulic systems, and which can reduce the number of components and the number of assembly steps.
In order to achieve the above described object, the present invention provides a brake assembly for a motorcycle provided with a front brake and a rear brake respectively for a front wheel and a rear wheel. The brake assembly comprises first brake actuating means and second brake actuating means, and an electronically controlled braking system, having a first amount transmission system extending from the first brake actuating means connected to one of either the front brake or the rear brake. The electronically controlled braking system drives whichever one of the front brake and rear brake that is not connected to the first amount transmission means using an actuator, in accordance with a control signal output from electronic control means that receives detection values from each of first amount detection means for detecting an actuating amount of the first brake actuating means and second amount detection means for detecting actuating amount of the second brake actuating means and subjecting the values to computation, and outputs the control signal to the actuator based on the result of computation.
If the first brake actuating means is actuated, the front wheel brake is actuated via the first actuating amount transmission system and the actuating amount is detected by the first actuating amount detection means and output to the electronic control means. if the second brake actuating means is actuated, the actuating amount is detected by the second actuating amount detecting means and output to the electronic control means.
The electronic control means carries out computation based on the inputted detected values of the actuating amount, outputs control signals to a hydraulic control actuator, and the front wheel brake and rear wheel brake are actuated in accordance with these control signals.
Accordingly, one of the front wheel brake and the rear wheel brake is actuated via the first actuating amount transmission system, while the other is actuated via the electronically controlled braking system. Since the brakes are respectively actuated by independent systems, there is no interference between them, control is simplified and responsiveness is excellent.
The actuating amount transmission system can also be simplified, the number of components reduced, assembly and maintenance work can be carried out easily, and design freedom for the layout of the transmission system is increased.
The front wheel brake and rear wheel brake have brake caliper pistons arranged at two or less places so the caliper structure is simplified.
The electronically controlled braking system does not utilize mechanical control such as a control valve, which means that degree of freedom of electronic control is increased.
A second aspect of the present invention is a brake assembly of the first aspect described above, in which the first brake actuating means is a lever master cylinder, the second brake actuating means is a pedal master cylinder, the first amount transmission system is connected to a front wheel brake and the actuator actuates a rear wheel brake.
The first actuating amount transmission system connects the lever master cylinder and the front wheel brake and can be designed so as to be short, and the electronically controlled braking system has an actuator arranged close to the rear wheel brake and can also be designed so as to be short.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description